Missing pick sensor

ABSTRACT

A missing pick sensor for apparatus for stopping a loom for weaving wire warps when a pick is missing. The sensor comprises a resilient member attached to the loom and a member of insulating material at one end of the resilient member and bearing on woven fabric having wire warps. A conductive member is supported by the insulating member and extends therefrom and is positioned over the wire warps near the point of weaving a pick through the wire warps. Circuit means is utilized for conductively coupling the conductive member to a loom stop-motion circuit and the conductive member is so positioned on the insulating member as to make contact with the wire warps when a pick is missing to complete the loom stop-motion circuit.

Dec. 3, 1974 United States Patent [19] Murray MISSING PICK SENSORPrimary Examiner-James Kee Chi Attorney, Agent, or FirmCharles A. Blank,Esq.

Inventor: Fletcher A. Murray, West Columbia, SC.

ABSTRACT [73] Assignee: Uniroyal, Inc., New York, NY.

a u I M P S F A Ur Field of Search 139/370, 372, 348, 352

supported by the insulating member and extends therefrom and ispositioned over the wire warps near [56] References Cited the point ofweaving a pick through the wire warps. UNITED STATES PATENTS Circuitmeans is utilized for conductively coupling the 0-S- nmW mam .n w .m m Ce k .w.m n 0mm n t wh mnunm prwwk oun ts m S m mw w l i r o flm b S c mb m m s eea t v .1 muu wu eceilm im m m e n 0m 0 m at Coo n0 O c. t.mwm888 8 444 4 BBBWBW 999 9 1.11919 .3 .."l. u .m mm m .e ...ne mm o o b hpeaw fl Oh .l.l PSSFSC 289340 344556 999999 HHHHHH 775543 37557 59437 65940 647373 22222 2 Claims, 5 Drawing Figures sumaorz PATENTEL DEC 3 I974MISSING PICK SENSOR This invention relates to a missing pick sensor forapparatus for stopping a loom for weaving fabric having wire warps whena pick is missing.

One prior apparatus for stopping a loom when a filling pick is missingutilizes a contact strip which makes contact with a conductive head toclose a circuit for stopping the loom when a pick is missing. Thissensor requires critical positioning of the conductive head adjacent tothe warps and it could result in the occurrence of as many as tenmissing picks of one-half inch spacing before detection because thepositioning must allow for normal vertical warp movement which rangesfrom one-half inch to one and one-quarter inches. The prior sensor alsocontains moving parts and is of a more complex construction than isdesirable for purposes of reliability.

A fault detector for stopping a loom is also known which responds toslack in the fabric to stop the motion of the loom, but this faultdetector is not adapted to detect missing picks.

It is an object of the present invention, therefore, to provide a newand improved missing pick sensor for apparatus for stopping a loom forweaving fabric having wire warps when a pick is missing which avoids oneor more of the disadvantages of prior such apparatus.

It is another object of the invention to provide a new and improvedmissing pick sensor which has a high degree of reliability in detectingthe first missing pick in a wire weaving process.

In accordance with the invention, in apparatus for stopping a loom forweaving fabric having wire warps when a pick is missing, a missing picksensor comprises a resilient member attached to the loom and a member ofinsulating material attached to the resilient member and bearing onwoven fabric having wire warps. The apparatus also includes a conductivemember supported by the insulating member and extending from theinsulating member and positioned over the wire warps near the point ofweaving a pick through the wire warps. The apparatus also includescircuit means for conductively coupling the conductive member to a loomstop-motion circuit. The conductive member is so positioned on theinsulating member as to be out of contact with the wire warps when nopicks are missing and to make contact with the wire warps when a pick ismissing, the wire warps forming a portion of the loom stop-motioncircuit.

Referring now to the drawings:

FIG. I is a perspective view of a missing pick sensor constructed inaccordance with the invention in an operative position on a fabrichaving wire warps;

FIG. 2 is a plan view of the missing pick sensor;

FIG. 3 is a diagram, partly schematic, of a circuit responsive to themissing pick sensor for stopping the motion of the loom;

FIG. 4 is a schematic drawing of the missing pick sensor on a fabrichaving a filling pick at the proper position; and

FIG. 5 is a schematic view of the missing pick sensor on a fabricmissing a filling pick.

Referring now more particularly to FIG. 1, in which the arrow representsthe direction of fabric motion, and to FIG. 2 of the drawings, a missingpick sensor in accordance with the invention comprises a resilientmember attached to the loom 11. The member 10 may,

for example, be of spring steel. A member 12 of insulating material, forexample, nylon, is attached to theresilient member 10 and rides on wovenfabric 13 having wire warps 13a. The picks 13b of the fabric 13 may beof wire or may be of non-conductive textile material.

A conductive member 14, preferably comprising a wire, is supported bythe insulating member 12 and extends from the insulating member and ispositioned over the wire warps near the point of weaving a pick throughthe wire warps. Theconductive wire 14 may be fastened to the insulatingmember 12 by suitable nuts and bolts recessed in the insultating member12.

The conductive member 14. is so positioned on the insulating member 12as to be out of contact with the wire warps when no picks are missingand to make contact with the wire warps when a pick is missing. As willbe described subsequently, the wire warps form a portion of a loomstop-motion circuit. The missing pick sensor also includes circuit meanscomprising, for example, an insulated wire 15 for conductively couplingthe conductive member 14 to the loom stop-motion circuit.

Referring now more particularly to FIGS. 3, 4 and 5, a loom motor 16energized by a suitable alternatingcurrent supply has within its housinga transformer having a winding 17 for supplying a suitablealternatingcurrent voltage to a solenoid 18 which is connected to thewire 15 of the sensor. In FIG. 3 the wire warps of the fabric 13 areschematically represented as being grounded and are, therefore,effectively connected to grounded terminal of the transformer winding17. The solenoid 18 controls a mechanical pawl which stops the motion ofthe loom by forcing disengagement of the loom master clutch when thesolenoid 18 is energized.

Referring to FIGS. 4 and 5, in which the arrows represent the directionof fabric motion, when a filling pick is present at its normal location,the wire 14 on the insulating member 12 is not in contact with the warpsof the fabric 13, as represented in FIG. 4. However, when a pick ismissing the warps are no longer held in place at the position of thewire 14 and separate into an upper and lower system of warps. Asrepresented in FIG. 5, the sensor is so positioned on the loom that asthe warps move, for example, one-half inch for insertion of the nextpick, the upper system of warps contact the sensor wire 14, therebyclosing the loom stopmotion circuit of FIG. 3. Accordingly, the solenoid18 is energized and the motion of the loom is stopped.

The sensor may also be utilized when the weave design has picks whichare spaced at less than one-half inch because the missing pick can bedetected sufficiently early to prevent the warps from traveling beyondthe distance which it is possible to back up the loom, a distance of,for example, 6 inches. For example, if the picks were spaced 1/64 inchapart, more picks would be missing before the first missing pick wasdetected but the distance the warps would travel would be less than thedistance it is possible to back up the loom.

While there has been described what is at present considered to be thepreferred embodiment of this invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the invention, and it is, therefore,aimed to cover all such changes and modifi- 3 4 cations as fall withinthe true spirit and scope of the inber and positioned over the wirewarps near the vention. point of weaving a pick through the wire warps;

What is claimed is: and circuit means for conductively coupling saidcon- 1. In apparatus for stopping a loom for weaving fabric ductivemember to a loom stop-motion circuit, said having wire warps when a pickis missing, a missing 5 conductive member being so positioned on saidinpick sensor comprising: sulating member as to be out of contact withthe a resilient member attached to the loom; wire warps when no picksare missing and to make a member of insulating material attached to saidrecontact with the wire warps when a pick is missing, 7 silient memberand bearing on woven fabric having the wire warps forming a portion ofthe loom stopwire warps during normal operation of the loom 0 motioncircuit. when no picks are missing from the fabric; 2. A sensor inaccordance with claim 1 in which the a conductive member supported bysaid insulating said conductive member comprises a wire.

member and extending from said insulating mem-

1. In apparatus for stopping a loom for weaving fabric having wire warpswhen a pick is missing, a missing pick sensor comprising: a resilientmember attached to the loom; a member of insulating material attached tosaid resilient member and bearing on woven fabric having wire warpsduring normal operation of the loom when no picks are missing from thefabric; a conductive member supported by said insulating member andextending from said insulating member and positioned over the wire warpsnear the point of weaving a pick through the wire warps; and circuitmeans for conductively coupling said conductive member to a loomstop-motion circuit, said conductive member being so positioned on saidinsulating member as to be out of contact with the wire warps when nopicks are missing and to make contact with the wire warps when a pick ismissing, the wire warps forming a portion of the loom stop-motioncircuit.
 2. A sensor in accordance with claim 1 in which the saidconductive member comprises a wire.